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Goh V.,Paul Strickland Scanner Center | Dattani M.,Paul Strickland Scanner Center | Farwell J.,Mount Vernon Hospital | Shekhdar J.,Mount Vernon Hospital | And 8 more authors.
European Radiology | Year: 2011

Purpose: To evaluate the radiation doses delivered during volumetric helical perfusion CT of the thorax, abdomen or pelvis. Materials and methods: The dose-length product (DLP) and CT dose index (CTDIvol) were recorded and effective dose (E) determined for patients undergoing CT (4D adaptive spiral) for tumour evaluation. Image noise and contrast to noise (CNR) at peak enhancement were also assessed for quality. Results: Forty two consecutive examinations were included: thorax (16), abdomen (10), pelvis (16). Z-axis coverage ranged from 11.4 to 15.7 cm. Mean DLP was 1288.8 mGy.cm (range: 648 to 2456 mGy.cm). Mean CTDIvol was 96.2 mGy (range: 32.3 to 169.4 mGy). Mean effective dose was 19.6 mSv (range: 12.3 mSv to 36.7 mSv). In comparison mean DLP and effective dose was 885.2 mGy.cm (range: 504 to 1633 mGy.cm) and 13.3 mSV (range: 7.8 to 24.5 mSv) respectively for the standard staging CT thorax, abdomen and pelvis. Mean tumour CNR at peak enhancement was 1.87. Conclusion: The radiation dose imposed by perfusion CT was on average 1.5 times that of a CT thorax, abdomen and pelvis. The dose is not insubstantial, and must be balanced by the potential clinical utility of additional physiologic data. Further efforts towards dose reduction should be encouraged. © 2010 European Society of Radiology. Source


Saunders M.I.,Marie Curie Research Wing | Saunders M.I.,University College London | Rojas A.M.,Marie Curie Research Wing | Parmar M.K.B.,Medical Research Council Clinical Trials Office | Dische S.,Marie Curie Research Wing
International Journal of Radiation Oncology Biology Physics | Year: 2010

Purpose: To evaluate long-term late adverse events and treatment outcome of a randomized, multicenter Phase III trial of continuous, hyperfractionated, accelerated radiotherapy (CHART) compared with conventional radiotherapy (CRT) in 918 patients with advanced squamous cell carcinomas of the head and neck. Methods and Materials: Survival estimates were obtained for locoregional relapse-free survival, local relapse-free survival, overall survival, disease-specific survival, disease-free survival and for late adverse events. Results: The 10-year estimates (±1 standard error) for locoregional relapse-free survival, overall survival, disease-free survival, and disease-specific survival were 43% ± 2% for CHART and 50% ± 3% with CRT (log-rank p = 0.2); 26% ± 2% and 29% ± 3% (p = 0.4), respectively; 41% ± 2% and 46% ± 3% (p = 0.3), respectively; and 56% ± 3% and 58% ± 3% (p = 0.5), respectively. There was a small but significant reduction in the incidence of slight or worse and moderate or worse epidermal adverse events with CHART (p = 0.002 to 0.05). Severe xerostomia, laryngeal edema, and mucosal necrosis were also significantly lower with CHART (p = 0.02 to 0.05). Conclusions: Despite the reduction in total dose from 66 Gy to 54 Gy, control of locoregional disease and survival with CHART were similar to those with CRT. These findings, together with the low incidence of long-term severe adverse events, suggest that CHART is a treatment option for patients with low-risk disease and for those unable to withstand the toxicity of concurrent chemoradiotherapy. © 2010 Elsevier Inc. All rights reserved. Source


Alonzi R.,Marie Curie Research Wing | Taylor N.J.,Paul Strickland Scanner Center | Stirling J.J.,Paul Strickland Scanner Center | D'Arcy J.A.,and Cancer Imaging Center | And 4 more authors.
Journal of Magnetic Resonance Imaging | Year: 2010

Purpose: To assess the reproducibility of relaxivity- and susceptibility-based dynamic contrast-enhanced magnetic resonance imaging (MRI) in the benign and malignant prostate gland and to correlate the kinetic parameters obtained. Materials and Methods: Twenty patients with prostate cancer underwent paired scans before and after androgen deprivation therapy. Quantitative parametric maps for T1- and T2*- weighted parameters were calculated (Ktrans, kep,v e, IAUC60, rBV, rBF, and R2*). The reproducibility of and correlation between each parameter were determined using standard methods at both timepoints. Results: T1-derived parameters are more reproducible than T2*-weighted measures, both becoming more variable following androgen deprivation (variance coefficients for prostate Ktrans and rBF increased from 13.9%-15.8% and 42.5%-90.8%, respectively). Tumor R2* reproducibility improved after androgen ablation (23.3%-11.8%). IAUC60 correlated strongly with Ktrans, ve, and kep (all P < 0.001). R 2* did not correlate with other parameters. Conclusion: This study is the first to document the variability and repeatability of T 1- and T2*-weighted dynamic MRI and intrinsic susceptibility-weighted MRI for the various regions of the human prostate gland before and after androgen deprivation. These data provide a valuable source of reference for groups that plan to use dynamic contrast-enhanced MRI or intrinsic susceptibility-weighted MRI for the assessment of treatment response in the benign or malignant prostate. © 2010 Wiley-Liss, Inc. Source


Alonzi R.,Marie Curie Research Wing | Alonzi R.,Mount Vernon Cancer Center | Padhani A.R.,Paul Strickland Scanner Center | Taylor N.J.,Paul Strickland Scanner Center | And 5 more authors.
International Journal of Radiation Oncology Biology Physics | Year: 2011

Purpose: The antivascular effects of androgen deprivation have been investigated in animal models; however, there has been minimal investigation in human prostate cancer. This study tested the hypothesis that androgen deprivation causes significant reductions in human prostate tumor blood flow and the induction of hypoxia at a magnitude and in a time scale relevant to the neoadjuvant setting before radiotherapy. Methods and Materials: Twenty patients were examined, each with five multi-parameter magnetic resonance imaging scans: two scans before the commencement of androgen suppression, one scan after 1 month of hormone treatment, and two further scans after 3 months of therapy. Quantitative parametric maps of the prostate informing on relative blood flow (rBF), relative blood volume (rBV), vascular permeability (transfer constant [Ktrans]), leakage space (ve) and blood oxygenation (intrinsic relaxivity [R2]) were calculated. Results: Tumor blood volume and blood flow decreased by 83% and 79%, respectively, in the first month (p < 0.0001), with 74% of patients showing significant changes. The proportion of individual patients who achieved significant changes in T1 kinetic parameter values after 3 months of androgen deprivation for tumor measurements was 68% for Ktrans and 53% for ve By 3 months, significant increases in R2 had occurred in prostate tumor, with a rise of 41.1% (p < 0.0001). Conclusions: Androgen deprivation induces profound vascular collapse within 1 month of starting treatment. Increased R2 in regions of prostate cancer and a decrease in blood volume suggest a reduction in tumor oxygenation. © 2011 Elsevier Inc. Source

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